Combined Labeled Leukocyte and Technicium 99 Sulfur Colloid Bone Marrow Imaging: Differentiating Primary Pyomyositis Pseudotumor from Osteomyelitis and Multiple Bone Infarcts.

A 53 year old-female patient with lupus had undergone a cephalo-medullary nailing for a femur shaft fracture 30 years ago. This was complicated by osteomyelitis, requiring multiple debridement procedures and hardware removal. Recently, she developed a painful soft tissue mass in the same region, which was ultimately diagnosed as pyomyositis. Because of chronic bone changes due to her past history, traditional imaging could not differentiate between osteomyelitis infarction and pseudotumor. A combined indium-labeled leukocyte scan with a technetium-99 sulfur colloid marrow scan ruled out osteomyelitis and guided proper treatment without osseous debridement and thus prevented unnecessary cross-contamination of the bone.